It seems like every weekend, one or more of our kids wants to spend the night at a friends house (or have them stay at ours). They have great friends from great families, but it just seems to be every weekend. Do you understand our dilemma?

Do I ever?! We had the same situation with our first born. It was weekend after weekend. It wasn't that the kids were doing anything wrong, it was just a case of a good idea out of control. Some of the down sides of it were that kids would show up on Saturday morning exhausted because they would stay up so late with their friends, and it would throw a "wet blanket" over their ability to get their chores done. We solved it simply by setting limits. We broke it down this way: one sleepover per semester, one per major holiday (Christmas and Easter Break), one for their birthday, and one per summer. It brought everything under control and we all lived happily ever after.